Point-of-sale payment terminals are physical checkout devices currently used for credit, debit and smart card transactions, typically used in shops and small businesses and mainly owned by merchants and banks. These devices capture payment information at the point of sale and quickly transfer it from the merchant counter to the payment network for approval. An example provider is VeriFone™. Current products enable support for multiple applications or services—such as loyalty programs, payment, smart card processing—at the point-of-sale. Furthermore, multiple applications, created by different developers, can reside on one terminal and yet remain separate. Various handheld and countertop peripheral products support multiple options for secure PINpad and smart card applications at the point of sale. These products allow merchants to accept both debit and smart card forms of payment.
However, various types of software attack are possible on these systems, additionally there is a danger that the merchant may cheat the customer out of money by putting through too much money or putting through a transaction twice.
It is desirable to improve this situation.